Radial gaskets of the aforesaid type are well known, and in use they generally comprise, besides the mentioned features, another dynamic sealing lip acting on the shaft surface at the end opposite to the one where pressure is exerted. The main sealing lip is also usually maintained in sealing position against the shaft surface by means of a suitable spring, such a helicoidal spring annularly positioned on the outside of same, and capable of developing a radial action towards the axis of the shaft.
Gaskets of this type, as manufactured and used up to now, generally present a main lip which has an externally limiting surface which is designed to be submitted to the fluid pressure, and which forms with the gasket axis a predetermined angle. That angle is obviously going to increase in value after the mounting of the gasket on the shaft, and the subsequent rotation of the lip around the relevant articulation lines. In any case, in the known configurations this angle, called the cutting angle, always shows a value substantially lower than 60.degree., so that when the gasket is in its working position this surface essentially has the shape of a truncated cone with an apex on the shaft axis inside the sealing ring of the gasket.
These known gaskets have not, however, provided entirely satisfactory results, particularly in connection with those uses previously described, primarily due to the blow-by of the damper liquid which occurs, particularly after the prolonged use of same.
It is therefore an object of this invention to provide a radial gasket of the aforementioned type and for the stated uses, which now permits the strict avoidance of any fluid blow-by in connection with its dynamic sealing aspects. It is another object of this invention to provide a gasket of this type which also allows for improved static sealing in connection with the closing surface of the cylinder, especially in dampers, such as those of the McPherson type.